Concrete block forming machine with impact head



April 22, 1958 F. NETH ET AL 2,831,230

CONCRETEBLOCK FORMING MACHINE WITH IMPACT HEAD Filed April 5, 1954 3 Sheets-Sheet 1 INVENTORS ZWZ'ZeS Davies and April 22, 1958 F. NETH ET AL 2,831,230

CONCRETE BLOCK FORMING MACHINE WITH IMPACT HEAD Filed April 5, 1954 3 Sheet sSheet 2 f INVENTORS Miles Davies and BY F Neih April 22, 1958 Filed April 5, 1954 'F. NETH ET AL 2,831,230

CONCRETE BLOCK FORMING MACHINE WITH IMPACT HEAD 3 Sheets-Sheet 3 FIG'. 7. END

FIG. 6. VIBRATION FIG. 5. IMPACT ENDS 1/ /I 0 FIG. 4. BEGIN IMPACT I I FIG. 2. START I I :N in P 310 3 a DISTANCE i m J I E INVENTORS Miles Dcz vies and BY I F Ne'llh Hfi'y a concrete block.

United States CONCRETE BLCCK FORMING MACHENE WITH IMT ACT I-EAD Application April 5, 1954, Serial No. 429,995

4 Claims. (Cl. -41) Our invention relates to concrete block forming machines of the general type illustrated in United States Letters Patent No. 2,620,541, issued December 9, 1952, to applicants herein and entitled Machine for Molding Concrete Blocks. it also relates generally to United tates Patent No. 2,589,115 issued March 4, 1952 to Russell B. Nelson, Miles Davies and Fred Neth and entitled Machine for Making Concrete Blocks. In this general type of machine, concrete blocks are formed by initial compression induced by a vertically reciprocating head and thereafter by the application of vibration to said mold and to said head to solidify said blocks while they are being formed in said mold.

One of the things we have discovered is that the initial formation of a concrete block may be accelerated by striking the concrete mixture a sharp blow initially before the vibration, thus to compact the material of which the block is to be made. Said impact and consequent compaction increase the rate of formation of the blocks substantially and produce a more solid block and one which conforms closely to the configuration of the mold.

in the two United States patents heretofore described, the initial compaction of the head was mainly induced by the application of pressure through said compacting head and thus some substantial interval of time was consumed in forcing the more or less plastic material of which the block is made into the bottom of the mold. This is due to the fact that we use a relatively dry mix and a substantial period of time must be consumed in causing the aggregate particles to adjust themselves in the mold and to crowd out the interstices between particles until they form a compact mass. We have discovered that this initial formation of a block may best be produced by striking said plastic material a sharp blow as for example, comparable to the action of a drop hammer. Thereafter, while the head is maintained at its lowermost position vibration is induced to cause the head to follow down and further compact the mass forming such Inasmuch as it is necessary to utilize substantial force to produce a blow of this magnitude and due to the fact that the framework of such machine will sustain blows of this character only to a limited degree, we have discovered that if said compacting head is left free to float upon springs directly underlying it, that said head can be thrown downward with a flail-like action so that its mass will. tend to carry through. We are able to minimize the reaction of the blow and the shock to which the frame would otherwise be subjected.

It is thus a principal object of our invention to provide a machine of this character with such a free fioating type of head which may be thrown with a flail-like action against the material in the mold box and, after the kinetic energy is thus utilized and spent, to utilize the further movement of said fio ating head to induce pressure upon the cementitious material forming the block to aid the vibration developed within the mold to compact the concrete block to its eventual form.

atent 'ice A inafter described with reference to the accompanying drawings in which: I

Figure 1 is a front elevation of a machine embodying our invention with portions thereof shown broken away away to disclose details of our invention; 7

Figures 2 to 7,inc1usive, are enlarged detail views of one end of said floating head, its connections and the di: rect spring support therefor, as said parts move sequentially from the initiation of the downward movement of the said head to its eventual position where the concrete block is completely formed; and,

Figure 8 is a graphic representation of the relationship of the head, the piston which moves it, integrated with head, piston travel and time, and correlated with the steps of impact, vibration and eventual compaction.

The general details of our invention are similar tothe machine illustrated in our United States Letters Patent No. 2,620,541, issued December 9, 1952, and entitled Machine for Making Concrete Blocks. Reference is made to the drawings and specification of said patent for the general details of said machine and to the over-all method of operation thereof, inasmuch as our present improvement relates only to a portion of said structure and to a portion of the cycle followed in the formation of a concrete block. t

To permit ready reference to our United States Patent N 0. 2,620,951, similar reference characters will be utilized as the details of our present improvement relate to those in said patent. I

A concrete block making machine embodying our invention comprises a rectangular frame 1. Projecting forwarclly from said frame 1 are two pairs of eyes, an upper pair 2 and a lower pair 3. Said eyes receive tubular sleeves 4 which reciprocate therein. The lower' ends of said sleeves are joined together below the eyes 3 by a horizontal beam 5 which is secured to said sleeves by bolts. The beam is supported at its center upon the upper end of a piston rod 6, which is secured thereto. The opposite end of the piston rod is connected to a piston which is movable vertically within a double acting hydraulic stripper cylinder 7. v

The stripper cylinder is secured to an H-shaped bracket 8 which projects from the front of said frame. The bracket 8 is formed with laterally projecting flanges 9 on its upper edge to provide support for the upstanding pedestals 10 which are secured thereto. A shoulder 11 is formed about each of said pedestals intermediate the ends thereof. Removable bumpers '12 each have a hollow end which slidably engages the upper end of the pedestals. Coil springs 14 encircle the engaged portions of said pedestals and bumpers and abut at their ends against the opposite faces of said shoulders. In the relaxed position of said springs, the telescoping ends of the pedestals and bumpers are spaced apart, and may be moved together by compressing the coiled springs 14. The upper ends of the bumpers are arranged to contact the beam 5 as the latter approaches its lowermost position.

A pallet beam 15 extends transversely between the sleeves 4, intermediate the upper and lower eyes 2 and 3 respectively, and is secured'thereto. Since the beam 5 and the pallet beam 15 are secured firmly to the sleeves 4, the unit so formed is here referred to as the stripper assembly. This assembly reciprocates vertically as the double acting cylinder 7 is actuated. A platform 16 projects forwardly and rearwardly from the center of said beam. Coil springs 17 rest at the lower ends of said platform, and support at their upper ends a pallet table 18. Bolts extend axially through said springs and slidably through the holes provided in the platform and table to secure said springs in place. Adjustment screws 19 rest at their lower ends upon said platform and support at their upper ends a pallet 20. Adjustment screws 19 are provided upon the platform 16 for vertical adjustment and are providedwith lock nuts for securing said screws in any desired position. The adjustment screws are arranged to contact the pallet table 18 to prevent excessive rocking of the latter during vibration. The pallet table is proportioned and arranged to support pallet 20 upon which the concrete blocks to be formed are carried from the machine after they are manufactured. Accordingly, when the stripper assembly reciprocates vertically, the pallet 20 reciprocates in a similar manner. 7

A concrete block mold 22 is held suspended above the pallet table 18 by the free ends of pairs of elongated spring members 23. Said spring members preferably comprise a plurality of leaves 24, 25, 26 and 27. Said spring elements are elongated flat strips of spring steel which are held in substantial parallelism with each other. Said spring elements and the leaves thereof constitute cantilever members supported at one end with their free ends joined together by a screw element 31, which passes through the ends of each of said leaves. Said leaves are spaced apart by spacers 32 encircling said screw element 31, and the lying intermediates certain of the leaves of the spring elements. That isto say, said spacers lie between the leaves 24 and 25, and between the leaves 25 and 26. t Spacing the leaves 26 and 27 apart are pad eyes 33 secured to the sides of the concrete block mold 22 as by cap screws or other appropriate securing means. The screw element 31 at each side of the concrete block mold 22 is joined by a connecting rod 35. The upper end of each connecting rod is bifurcated, as. of 35a, straddling an eye at the lower end of the screw element 31 and being joined thereto by a pin 36. The lower end of each of said connecting rods has an eye 35b formed thereon. In the bore of said eye is an eccentric cam (not shown) fixed to drive shaft 38. Thus, said drive shaft as it rotates, rotates the eccentric cam and reciprocates the connecting rod operatively joined thereto back and forth. The movement of the upper end of each of said connecting rods 35 transmits motion to the screw element 31 fixed thereto and this motion is transmitted to the concrete block mold 22 which is joined to the upper ends 350 of the connecting rods through the pad eyes 35, at each side of the concrete block mold 22.

'As is described in said United States Patent No. 2,620,541, the eccentric movement of the lower end of said connecting rods is not transmitted to the concrete block mold 22 due to the fact that the pin 36 journals in the bifurcated end 35a of the connecting rod and thus the mold block is limited to the path defined by the free end of the spring elements, referred to generally as 23.

Because said spring elements are relatively long and are secured at one end and are free at their ends carrying the screw element 31 at which they carry the concrete block mold 22, said mold is limited to more or less pure vertical movement.

The material of which concrete blocks are made in our machine is deposited from a hopper (not shown) by feeding means which are not particularly pertinent to an understanding of our present invention and which are thus not described in detail. They are described in detail, however, in United States Patent No. 2,589,115 and reference is had to said latter patent.

We preferably provide a substantially dry mixture which flows into the concrete block mold as it is supported by the pallet 20 which underlies and seals the bottom of said mold 22. That is to say, said concrete block mold 22 comprises ends and sides and is open at the top and bottom with the pallet 20 underlying and sealing said bottom. When concrete blocks are being formed within the said mold, the pressure head 44 carried by the beam 4.4a enters through the top of the mold and compresses and thereafter continued pressure is applied to the ma terial of which said concrete blocks are made while said mold is being subjected to vibration produced by the rotation of the drive shaft 33 acting through the connecting rods and fixing the elongated spring members as has been heretofore described.

Thereafter, the pallet 20 is lowered by the stripper assembly and the blocks which have been compressed and vibrated are now so firm that they will not crumble and collapse. The retraction of the pallet is in a vertical plane and thus is parallel to the vibrational path eliected by the movement of the connecting rods. The pallet is relatively slowly moved downwardly and the blocks are ejected while resting upon the pallet. All of the foregoing, save impact, is defined in and covered by the two United States patents which have heretofore been identified, and are referred to only to give a proper setting for our present invention. In said prior machines, the movement of the pressure head was initiated and then clamped by toggle links so that the pressure applied to the top of the material of which the blocks were made was a slow, continued application of pressure, without impact.

In our present improvement, we have arranged operating cylinders 45 upon each side of the sleeves 4, as is illustrated best in Figure I. Said operating cylinders are double acting hydraulic cylinders with fluid connections 46, 46a at ,the top and bottom thereof, respectively. A piston 47 is arranged within each of the operating cylinders and the fluid connection 46 lies above the piston in each cylinder while the fluid connection 46a lies beneath it. Thus, fluid introduced through the fluid connection 46 will cause the piston to move rapidly downwardly, while entrapped fluid flows outwardly through the connection 46a. When the operation is reversed, fluid introduced through the connection 46a forces the piston 47 upwardly and the liquid above it is forced out through the connection 46. Piston rod 48 has a head 49 thereon, lying within a pocket 50 at each end of the beam 44a. Also enclosed within each pocket is a compression spring 51, which encircles the upper end of the piston rod 48 and underlies the head 49. Said compression spring 51 bears at its lower end upon the floor 50a of said pocket.

Carried by the under surface of each of the ends of the beam 44a is a limit pin 52. Axially aligned with each of said pins is a stop 53 carried by the upper surface of the pallet beam 15. Adjusting screws 54 are carried by the upper ends of each of the stops 53 to make minute and precise adjustments for varying the point of impact between the lower end of the limit pins 52 and the heads of the said adjusting screws 54.

When fluid is introduced through the connection 46, it causes the piston 47 to be driven downwardly quite rapidly. The pressure head 44, its beam 44a, and the other mechanism associated therewith are quite massive and possess substantial inertia. Thus, the initial movement of the piston compresses the spring 51 in its pocket 50, as is illustrated in Figure 3. Reference is made to Figures 2 and 3 to illustrate this point. The head initially does not move, only the spring 51 compresses. The continued movement of the piston toward its lower end causes the head and its beam to be flipped downwardly. The motion of the piston in its cylinder is timed so that the spring 51 never elongates to its original position while the head and its beam move downwardly. When the piston reaches its lowermost point as is shown in Figure 4, the lower end of the limit pin 52 still has some distance to travel before it strikes the upper end of the adjusting screw 54. This causes the head 44 to strike the material in the mold box 52 a severe blow and to compact it severely.

Said mold is subjected to vibration prior to the time the head 44 is brought downwardly and thus the pressure exerted through the compression of springs 51 at each side of the beam 40a causes said head to be pressed against the material of which the concrete block is to be formed with a great deal of force. The energy stored Within the said springs thus is expended as the head moves slowly from its position in Figure 5 through the position it assumes in Figure 7 until the lower end of the limit pin at each end of the beam bears upon the upper surface of the adjusting screw 54 aligned therewith. At this point, the compression springs 51 at each side of the beam 41:: are still under some slight compression.

A correlation of the movement of the piston and the head throughout the operating stroke of each is illustrated in Figure 8. The ordinates of said graph are indicated in distance travelled in inches and the abscissas are indicated in time. Thus, as is indicated in said graph, at the upper end of the stroke indicated as zero, there is a substantial time lag during which the piston travels downwardly approximately one-half inch before which the head commences to move. Thereafter, the piston travel is substantially at the same rate as that of the head, although the -ead travel tends to gain slightly thereon. When the piston has travelled almost eight and one-half inches, the head has travelled about eight inches, and it is at this point that the head makes contact with the upper surface of the material of which a concrete block is to be formed. The kinetic energy of the head and its associated beam is utilized as an impact force to initiate the compression and compaction of the material forming said block. This travels approximately to a point eight and one-half inches below the upper limit. Thereafter, vibration tends to cause the head to move downwardly to approximately the end of its stroke at eight and three-quarter inches. The piston is permitted to take its full stroke of nine inches and thus at the end of the stroke the springs 51 have not fully elongated but are exerting some continued pressure upon the head 44 as it bears against the concrete block. If the molds are correctly filled and material of proper consistency is utilized, said concrete blocks are completely formed and are of sufficient compaction and rigidity to permit them to be removed from the machine upon a pallet. That is to say, said blocks thus formed are sufliciently compacted to maintain their form without slumping, cracking or crumbling.

We claim:

1. In a concrete block forming machine, an impact member movable in a vertical path toward and away from a mold box to compact first by impact and then by a constant compressive force the block forming material in the box, at least one vertically reciprocal fluid motor means for efiecting the vertical impact movement of said impact member, said fluid motor being operatively connected to said impact member with a vertical rod means slidably carried in an aperture in the impact member so as to allow relative movement between the rod and impact member, said vertical rod terminating in an enlarged head the upper face of which is adapted to bear upon the impact member during vertical movement of the head away from the mold box, and a compression spring mounted intermediate said head and that portion of said impact member which carries said aperture, the vertical reciprocation of said fluid motor being controlled to terminate with said spring under compression and with said head out of contact with the impact member so the terminal portion of the movement of the head is eflected by the compressive force of the spring rather than by continued operation of the fluid motor.

2. In a concrete block forming machine having a frame member resiliently supporting a mold box, vibration means for oscillating said mold box vertically, an elongated impact member movable in a vertical path toward and away from said mold box to compact the block forming material in the box, a pair of parallel and vertically reciprocal fluid motor means for effecting the vertical movement of said impact member, each said fluid motor being operatively connected to said impact member by means of avertical rod which slidably is carried in an aperture in the impact member and which terminates in a head the upper face of which is adapted to bear upon the impact member during vertical movement of the head away from the mold box, and a compression spring mounted intermediate the lower face of each said head and that portion of said impact memher which carries said aperture, the vertical reciprocation under compression and said head out of contact with the impact member.

3. A concrete block forming machine comprising a frame, a pallet support resiliently mounted upon said frame and carrying a mold box, vibration means for oscillating said mold box vertically, an impact head movable in a controlled path vertically toward and from said mold box, a reciprocal fluid motor having a limited stroke operatively joined to said impact head through the intermediate agency of a coiled compression spring, whereby reciprocation of said fluid motor compresses the spring yieldably to initiate movement of said impact head toward said mold box, and control means for actuating said fluid motor so the stroke thereof leads the vertical movement of said impact head and for terminating the stroke with said spring under compression so the terminal portion of the movement of the head is effected by the compressive force of the spring rather than by the fluid motor.

4. A concrete block forming machine comprising a frame, a pallet support resiliently mounted upon said frame and carrying a mold box, vibration means for oscillating said mold box vertically, an impact head movable in a controlled path vertically toward and from said mold box, a reciprocal fluid motor having a limited stroke operatively joined to said impact head through the intermediate agency of a coiled compression spring means,

,. whereby reciprocation of said fluid motor compresses the spring yield-ably to initiate movement of said impact head toward said mold box and when the motor approaches the limit of its stroke it throws said head toward the mold due to the resiliency of said member, and an adjustable stop means, carried in part by said head and in part by said frame, to terminate the movement of said head toward the mold box at a point where said spring is under compression and yieldably urging the head toward the mold box.

References Cited in the file of this patent UNITED STATES PATENTS 755,818 Venables Mar. 29, 1904 1,604,107 Tackett Oct. 19, 1926 2,341,012 Billman et a1. Feb. 8, 1944 2,589,115 Nelson et al. Mar. 11, 1952 2,602,507 Adams July 8, 1952 

